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| Home > Publications database > Morphologie und Energetik kleiner Bleikristalle untersucht mit Rastertunnel- und Rasterelektronenmikroskopie |
| Home > Publications database > Morphologie und Energetik kleiner Bleikristalle untersucht mit Rastertunnel- und Rasterelektronenmikroskopie |
| Book/Report | FZJ-2020-01143 |
2001
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
Jülich
Please use a persistent id in citations: http://hdl.handle.net/2128/24373
Report No.: Juel-3917
Abstract: Precise measurements of the equilibrium crystal shape yield information an varioussurface energetic parameters. For this reason a system combining scanning tunnelingand Scanning electron microscopy has been developed and built up. In this work theshape of small lead crystals is investigated. A major issue is the achievement of thethermodynamic equilibrium. Therefore measurements of the crystal shape have beenperformed at several temperatures in the range between 300 K and 510 K using avariable-temperature scanning tunneling microscope. The temperature dependence ofthe shape of the (111)-facets, which form an the crystals, is used for the absolutedetermination of kink and step formation energies. In this context it is shown thatcontributions due to phonons have hardly any effect an the values obtained. Themeasured shape of the area vicinal to the facet can be described by a universal exponentof 1.51 ± 0.06. This is in very good agreement wich the Pokrovsky-Talapov exponentof 3/2. Hence the step interaction energy can be estimated. By using the step freeenergies determined before, geometric measurement of the regular three-dimensionalcrystal shape also allows the absolute determination of the surface free energies of lowindexfacet orientations and the step free energies of the corresponding vicinal areas.Eventually a new method for the determination of absolute energies is presented, whichmakes use of the temperature variation of the facet radius.
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